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Common Chicken Diseases and Treatments

Chickens get sick just like you and me. The only problem is, your hens, chicks, and roosters don’t tell you when they are sick, and some chicken illnesses don’t have noticeable signs until they become a severe disease. As a chicken owner, it is important to know the most common chicken diseases and their treatments to avoid an entire flock of sick birds.

chicken disease

Each of these chicken diseases can become a serious problem if not treated properly. Our descriptions and treatments are not to be used as a replacement of a real veterinary diagnosis. Always consult a professional before giving your chickens any medication.

Each of these common chicken diseases is listed with a picture so the illnesses can be easily identifiable. Some pictures contain images that some may find very unpleasant.

Avian Influenza (Bird Flu)

Avian Influenza bird flu

Symptoms: Sudden death; lack of energy; no appetite; egg production stops; soft-shelled or misshapen eggs; swelling of the head; purple discoloration in the eyelids, comb, and hock; nasal discharge; coughing; sneezing; diarrhea; lack of coordination.

Cause: Viral disease. Most commonly spread from an infected bird or carried on boots and feed bags.

Keep wild birds away from your flock, add a tarp above your run/coop to protect your chickens from wild bird droppings. Clean off your boots before entering your coop/run. Never leave a feed bag in your coop/run (feed factories attract infected birds and the feed bags could carry the virus)

Suggested Treatment: If any of your birds contract bird flu, they need to be put down humanely. There is no cure and antibiotics will not help. Sanitize any area where infected birds, objects, or other animals were before introducing new chickens.

The best policy is to SANITIZE EVERYTHING before introducing it to your flock. Anything can be a potential carrier of this disease, so sanitize often to keep your birds healthy.

Speak to your vet for more information on Avian Influenza and possible vaccines to use before your flock is sick.

Avian Pox/Fowl Pox

Avian-Pox disease

Symptoms: Wart-like, white spots on the skin, combs, and mouth. Ulcers in the mouth and trachea. Egg laying stops.

Cause: Contaminated surfaces, other birds with pox, and mosquitoes. This is a viral disease.

Suggested Treatment: Separate the infected bird and keep in a warm dry place to recover. Feed the chicken soft food and there is a good chance your bird will survive the illness.

There are vaccines available for Avian Pox. Talk to your vet for more information.


Symptoms: Tremors (these will progress into total body paralysis, which includes the muscles they use to breathe, if not treated.), feathers are easy to pull out.

Cause: Contaminated food/water. Dead meat left near food and water.

Suggested Treatment: A relatively expensive antitoxin is available (speak to a vet). If caught early, some chicken owners have used 1 tsp of Epsom salts dissolved in 1 ounce of warm water. Drip the mixture on the into the crop several times per day.

This disease can generally be avoided if you keep your flock’s water and food source sanitized.


Symptoms: Blood or mucus in droppings, weak, pale comb & skin, little to no appetite, inconsistent egg laying (or none at all), diarrhea.

Cause: This intestinal disease is spread very easily, unfortunately. It is caused by a parasitic organism that thrives in warm, humid, and wet conditions. Coccidiosis can be passed via shoes, shovels, contaminated water & food, and droppings.

Suggested Treatment: If one of your birds is infected with this disease, you will need to treat the whole flock. Separate the sick chickens from the rest of your flock as soon as possible, and make sure you clean out the coop. Ensure that the living and feeding space is clean and dry. There are medications and treatments available and you should discuss those with your vet.

Basic hygiene and sanitation is the first step in preventing Coccidiosis. If your chickens haven’t had a vaccination for this disease, you can use medicated starter feed to try and avoid the issue.

Fowl Cholera

Symptoms: Swelling of the comb and wattles, discharge from the mouth and nose, greenish/yellowish diarrhea, troubles breathing, darkened head or wattle, obvious joint pain.

Cause: Bacterial disease. Contracted from contaminated food or water. It can also be spread by wild birds, raccoons, and other wild animals.

Suggested Treatment: No real treatment. You will have to humanely put the infected birds down, as they will always be carriers if they survive.

Usually found in birds over 4 months.

Infectious Bronchitis

Symptoms: Chickens sneezing, snoring, and coughing. Drainage from the nose and eyes. Decreased egg production – eggs may be misshapen, soft-shelled, and watery inside.

Cause: This is a viral disease that is highly contagious. It is spread through the air, contact with infected birds, and contaminated areas.

Suggested Treatment: Vaccines and medications are available (see your veterinarian). Extra attention and care. Some chicken owners suggest you keep the sick chickens warm with a heat lamp. If you choose to do so, make sure there is no way for it to cause a fire.

50% mortality in chicks under 6 weeks.

Infectious Coryza

Symptoms: Swollen face, eyes swollen shut, sticky discharge from the eyes and nose, sneezing & coughing, moist area under the wings, egg laying stops.

Cause: Coryza is a bacterial disease that is transmitted through carrier birds, contaminated drinking water and surfaces the bacteria was exposed to.

Suggested Treatment: There are antibiotics for this, but none are a guaranteed cure. The infected birds will have to be put down humanely, as they will always be a carrier of the disease.

You can keep your flock relatively safe from this disease as long as you keep your chicken’s coop and water clean. Also, make sure your flock doesn’t come into contact with other random birds.

Marek’s Diseasemarek's disease

Symptoms: tumors inside and outside the body, leg/wing paralysis (or full paralysis), cataract-looking eyes, ruffled feathers

Cause: This viral disease is very contagious; contracted via feather dander, skin particles, other infected birds.

Suggested Treatment: There is no treatment for this disease.There is a vaccine available, but you must decide to get your chickens vaccinated before they hatch, or within 24 hours of hatching.

Primarily affects chickens under 20 weeks.

Moniliasis (Thrush)

Thrush disease in chickens

Symptoms: White, oozy substance in the crop (space between neck and body), slowed egg production, ruffled feathers, crusty vent area, increased appetite, inflamed vent area

Cause: Moldy feed or other moldy food, contaminated water, or tainted areas

Suggested Treatment: Can be treated by using an anti-fungal medicine (talk to your vet). Be sure to remove bad food and keep the water source fresh and clean.

Mycoplasmosis/CRD/Air Sac Disease

mycoplasmosis disease in chickens

Symptoms: Weakness/fatigue, poor egg production, coughing, sneezing, difficulty breathing, swollen joints

Cause: Spread through other birds (wild birds carry this also). Can be transmitted from hen to chick through the egg.

Suggested Treatment: If administered early, antibiotics from your vet can treat this disease.

Newcastle Disease

Symptoms: Difficulty breathing, wheezing, cloudy eyes, egg production stops, nasal discharge, paralysis of the legs/wings, twisted necks

Cause: This viral disease is highly contagious and can be contracted through infected chickens and other wild birds. This virus can also be carried by shoes, clothing, and infected surfaces.

Suggested Treatment: There really isn’t a treatment for this disease. There is not a very good chance of survival in younger birds and chicks, but birds that survive do not continue carrying the disease. A vaccine is available for Newcastle disease (see your vet).

Omphalitis (Mushy Chick)mushy chick disease

Symptoms: unpleasant smell, drowsy chick (usually newly hatched), enlarged, inflamed, blueish midsection, fatigue/weakness

Cause: This is a bacterial infection of the naval from unclean surfaces or infected chicks. Chicks with weak immune systems are likely to contract this disease.

Suggested Treatment: Antibiotics and sanitizing can sometimes help. However, most chicks that become infected will die. Separate the healthy chicks as soon as you notice signs of this disease.

Use caution while handling chicks with this disease, as staph and strep can infect humans. Make sure to always sanitize yourself after handling sick chicks.

Pasty butt

Symptoms: pasted vent, poop left on the behind of a chick, inflamed/red vent

Cause: Stress, being too cold, over-heating, improper diet (less common)

Suggested Treatment: Wash the infected chick’s butt with lukewarm running water. Once droppings are soft enough, gently wash the poop off the down without pulling. Be careful to avoid tearing the chick’s skin.

Once the vent has been clean, towel dry the chick and use a hair dryer to dry the down completely. It’s best to keep a chick with pasty butt separate from others until swelling and redness has subsided. Otherwise, the other chicks might peck at the infected area and cause more problems.

PullorumPullorum disease in chick

Symptoms: In chicks – little to no activity, white paste on their backside, signs of difficult breathing. Some chicks can die without showing signs at all.

In older birds – sneezing, coughing, poor egg production.

Cause: This is another viral disease, which is contracted through carrier birds and contaminated surfaces, such as clothing.

Suggested Treatment: There is no vaccine or treatment suggested. Infected birds should be humanely put down.

chicken disease doctor

The more you know about poultry health, the better you’ll be at caring for your backyard flock. However, nothing can replace the diagnosis by a proper veterinarian, so if you don’t already have a chicken doctor, look online or ask around to find the vet that’s right for you.

The chicken experts at Cargill can also be a great source of chicken information. Visit their website and Twitter to continue learning about chickens and keeping your birds as healthy as possible.